Lilly, Laurenz, Yeliz, Marie, and Karol find diamonds on the Elbe beach, hidden inside of cuttlefish. When they have the gemstones examined by an expert, gangsters try to take away the valuable find. The peppercorns are barely able to escape the crooks and flee to Lilly's father, the head of Port Security.
Laurenz, Yeliz, Lilly, Marie, and Karol come on the trail of research by Kenyan journalist Mado criminals. The criminals sell fake, ineffective drugs to Africa. Mado was attacked by the counterfeiters when they caught him investigating their warehouse. Lilly and Karol are also surprised at spying.
Lilly's grandmother's car is stolen with Lilly's precious cat Harmony inside. Lilly immediately summons the peppercorns and the five set out on a dangerous search for the thieves.
Yeliz faints on the playground and Lilly finds diet pills with her. Laurenz examines the pills and they turn out to be illegal and extremely harmful to health.
Laurenz witnesses Moritz being beaten and filmed by older students, a clear case of "happy slapping": the perpetrators film their victims and put the videos on the Internet.
Laurenz needs to get his mother 500 euros at the ATM, but he doesn't notice that a rogue couple using a hidden micro-camera and a reader spied on the debit card's account data. The next day, his mother accuses him of taking more money than agreed from her account. Laurenz and the other peppercorns try to find the true thieves.
Pia, the director's daughter, quarrels with Therese from Togo. When Lilly and Yeliz visit Therese for their birthday, they find an empty apartment. From a neighbor they learn that Therese and her mother left the apartment in a hurry shortly after Pia visited them. What's going on there?
The peppercorns must move out of their headquarters. Laurenz's parents want to sell the warehouse floor in the Speicherstadt to the investor Mr. Meyer. The peppercorns find out that Meyer is the boss of a far-right youth organization. Yeliz gets caught trying to film the troupe. But the peppercorns do not give up.
First the letterbox explodes, into which Laurenz and Marie have just thrown the envelope with signatures against animal experiments. Then Laurenz finds out that his best friend Karol has a crush on his girlfriend Yeliz. Laurenz swears that he will bring down the bombers, alone, without the others. He puts himself and all the peppercorns before their greatest challenge.
Karol gets an old Madonna painting from his uncle Pawel. Although Pastor Leo blesses the picture, Karol is visibly unimpressed. He prefers to sell it for a small amount to a junk dealer to finally afford his coveted game terminal. Meanwhile, the peppercorns find out the true value of the "Black Madonna" on the Internet: it's around 20,000 euros. For Karol it is clear: he must get that picture back.
